It is known in the art to which this invention pertains to provide a suction accumulator between the evaporator and compressor of a refrigeration system in order to protect the compressor from possible damage. Vaporized refrigerant is received from the evaporator and passed on through the suction accumulator to the compressor. Any raw liquid is metered back to the compressor by the accumulator at a rate that will not result in damage to the compressor.
During operation of the refrigeration system, there are times when an unusual amount of refrigerant will collect in the suction accumulator. For example, when the system is shut off, such as in the case of an intermittently operated air conditioning system, the refrigerant tends to condense in the entire system and collect in the accumulator. A similar situation may occur when the system is operated under low load conditions. Generally speaking, in the situations described, the metering orifice in the lower end of the stand pipe of the suction accumulator is quite adequate to assure that liquid refrigerant is delivered to the compressor at a non-harmful rate.
Unforeseen circumstances may arise, however, which cause what is termed in the art a "major flood back" of the accumulator. Stated otherwise, in this situation the liquid level capacity of the suction accumulator, or its design limit, is exceeded. To explain further, an accumulator is normally sized as to holding capacity to store only that percentage of refrigerant charge as will not cause damage to the compressor. This may vary from 25 to 75 percent of the total charge. Should this volume be exceeded by a major flood back, which illustratively may be caused by failure of the expansion valve in the refrigeration system, damage to the compressor may result.